EP0861918B1 - Verbessertes Packzementierungsverfahren für Gegenstände mit kleinen Durchgängen - Google Patents
Verbessertes Packzementierungsverfahren für Gegenstände mit kleinen Durchgängen Download PDFInfo
- Publication number
- EP0861918B1 EP0861918B1 EP98200741A EP98200741A EP0861918B1 EP 0861918 B1 EP0861918 B1 EP 0861918B1 EP 98200741 A EP98200741 A EP 98200741A EP 98200741 A EP98200741 A EP 98200741A EP 0861918 B1 EP0861918 B1 EP 0861918B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- organic material
- coating
- holes
- pack
- inches
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000576 coating method Methods 0.000 title claims description 59
- 239000002245 particle Substances 0.000 title 1
- 239000011368 organic material Substances 0.000 claims description 31
- 239000011248 coating agent Substances 0.000 claims description 28
- 238000001816 cooling Methods 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 11
- 239000000843 powder Substances 0.000 claims description 10
- 239000012190 activator Substances 0.000 claims description 8
- 150000004820 halides Chemical class 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 5
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical group N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 claims description 4
- 229910010293 ceramic material Inorganic materials 0.000 claims description 4
- 229920001971 elastomer Polymers 0.000 claims description 4
- 239000011253 protective coating Substances 0.000 claims description 4
- 239000005060 rubber Substances 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 3
- 239000004593 Epoxy Substances 0.000 claims description 2
- 229920001800 Shellac Polymers 0.000 claims description 2
- 239000004568 cement Substances 0.000 claims description 2
- 238000001704 evaporation Methods 0.000 claims description 2
- 230000008020 evaporation Effects 0.000 claims description 2
- 229920001296 polysiloxane Polymers 0.000 claims description 2
- ZLGIYFNHBLSMPS-ATJNOEHPSA-N shellac Chemical compound OCCCCCC(O)C(O)CCCCCCCC(O)=O.C1C23[C@H](C(O)=O)CCC2[C@](C)(CO)[C@@H]1C(C(O)=O)=C[C@@H]3O ZLGIYFNHBLSMPS-ATJNOEHPSA-N 0.000 claims description 2
- 239000004208 shellac Substances 0.000 claims description 2
- 229940113147 shellac Drugs 0.000 claims description 2
- 235000013874 shellac Nutrition 0.000 claims description 2
- 239000012815 thermoplastic material Substances 0.000 claims description 2
- 239000002966 varnish Substances 0.000 claims description 2
- 239000000470 constituent Substances 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 239000000463 material Substances 0.000 description 39
- 229910052782 aluminium Inorganic materials 0.000 description 22
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 22
- 229910000951 Aluminide Inorganic materials 0.000 description 16
- 229910000601 superalloy Inorganic materials 0.000 description 13
- 239000007789 gas Substances 0.000 description 10
- 229910052804 chromium Inorganic materials 0.000 description 9
- 239000011651 chromium Substances 0.000 description 9
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 239000010703 silicon Substances 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 6
- 238000005422 blasting Methods 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- -1 rubber cement Chemical compound 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000010941 cobalt Substances 0.000 description 3
- 229910017052 cobalt Inorganic materials 0.000 description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- 238000012856 packing Methods 0.000 description 3
- 239000000523 sample Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052727 yttrium Inorganic materials 0.000 description 3
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 238000005269 aluminizing Methods 0.000 description 2
- 230000001680 brushing effect Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000013383 initial experiment Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000011236 particulate material Substances 0.000 description 2
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 description 2
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 description 2
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- IRPGOXJVTQTAAN-UHFFFAOYSA-N 2,2,3,3,3-pentafluoropropanal Chemical compound FC(F)(F)C(F)(F)C=O IRPGOXJVTQTAAN-UHFFFAOYSA-N 0.000 description 1
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 1
- 241001474374 Blennius Species 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910021007 Co2Al5 Inorganic materials 0.000 description 1
- 229910021328 Fe2Al5 Inorganic materials 0.000 description 1
- 240000007049 Juglans regia Species 0.000 description 1
- 235000009496 Juglans regia Nutrition 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910000943 NiAl Inorganic materials 0.000 description 1
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical group [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- YYCNOHYMCOXPPJ-UHFFFAOYSA-N alumane;nickel Chemical class [AlH3].[Ni] YYCNOHYMCOXPPJ-UHFFFAOYSA-N 0.000 description 1
- 235000019270 ammonium chloride Nutrition 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 229910001610 cryolite Inorganic materials 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 125000003700 epoxy group Chemical group 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- 235000012907 honey Nutrition 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 239000011698 potassium fluoride Substances 0.000 description 1
- 235000003270 potassium fluoride Nutrition 0.000 description 1
- FJWLWIRHZOHPIY-UHFFFAOYSA-N potassium;hydroiodide Chemical compound [K].I FJWLWIRHZOHPIY-UHFFFAOYSA-N 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical group [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- 235000013024 sodium fluoride Nutrition 0.000 description 1
- ZIQRIAYNHAKDDU-UHFFFAOYSA-N sodium;hydroiodide Chemical compound [Na].I ZIQRIAYNHAKDDU-UHFFFAOYSA-N 0.000 description 1
- 239000002195 soluble material Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 235000020234 walnut Nutrition 0.000 description 1
- 239000001993 wax Substances 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/02—Pretreatment of the material to be coated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/32—Processes for applying liquids or other fluent materials using means for protecting parts of a surface not to be coated, e.g. using stencils, resists
- B05D1/322—Removable films used as masks
Definitions
- the present invention relates to an improvement in the method of coating superalloy articles with a protective coating using a pack diffusion process.
- the present invention provides an improved process for coating superalloy articles having small holes and apertures therein.
- Aluminide coatings have been well-known for a number of years and are widely used to protect metallic surfaces from oxidation and corrosion. Aluminide coatings are widely used in gas turbine engines because they are economical and add little to the weight of the part. Aluminide coatings are applied by a pack diffusion (or pack cementation) process. Other coatings are also applied by pack processes including silicon and chromium as well as alloys based on aluminum, silicon, and chromium.
- pack diffusion or pack cementation
- Other coatings are also applied by pack processes including silicon and chromium as well as alloys based on aluminum, silicon, and chromium.
- the term aluminide will be understood to encompass diffusion coatings based on aluminum, silicon, chromium and alloys and mixtures thereof.
- Aluminide coatings are formed by diffusing aluminum into the surface of the superalloy article to produce an aluminum-rich surface layer which is resistant to oxidation.
- Superalloys are high-temperature materials based on nickel or cobalt.
- Exemplary patents showing diffusion aluminide coating processes include U.S. Patent No.: 3,625,750, U.S. Patent No.: 3,837,901, and U.S. Patent No.: 4,004,047.
- aluminide coatings are applied by a pack process. In a pack process a powder mixture including an inert ceramic material, a source of aluminum, and a halide activating compound is employed. The powder materials are well mixed and the parts to be coated are buried in the powder mix. During the coating process an inert or reducing gas is flowed through the pack and the pack is heated to an elevated temperature.
- the pack coating process involves complex chemical reactions in which the halide activator reacts with the aluminum source to produce an aluminum-halide compound vapor which contacts the surface of the part.
- the vapor contacts the superalloy surface it decomposes, leaving the aluminum on the surface while the halide is released to return to the aluminum source and continue the transport process.
- the aluminum is deposited on the superalloy surface, it diffuses into the substrate. Diffusion is promoted by conducting the process at elevated temperatures, typically in the order of 1,500°F (816 °C) to 2,000°F (1093 °C). In the case of silicon and chromium-based coatings, similar reactions occur.
- NiAl nickel-base superalloys
- Other nickel aluminum compounds are often found further below the surface as are compounds between aluminum and the alloy elements in superalloy, including e.g., cobalt, chromium, titanium, and refractory materials such as tungsten, tantalum, and molybdenum.
- cobalt chromium
- titanium titanium
- refractory materials such as tungsten, tantalum, and molybdenum.
- chromium-based coatings a chromium enriched surface layer forms while in the case of silicon-based coatings silicide compounds form.
- the high turbine blades are invariably air-cooled to permit operation of the engine at higher temperatures.
- the cooling air is derived from air which is pressurized by the compressor section of the engine.
- the temperature of the cooling air has increased to the point where such "cooling" air may actually have temperatures as high as 600°F (316 °C) to 1,100°F (593 °C). It has been observed that such high temperature cooling air causes undesirable oxidation on the internal cooling passages of the turbine blades and other air-cooled gas turbine engine hardware.
- the internal passages and cooling holes in the blade with the aluminide coating so as to reduce oxidation.
- These holes typically have a diameter from about 0.010 inches (0.025 cm) to about 0.025 inches (0.064 cm) and a depth of typically from about 0.030 inches (0.076 cm) to about 0.300 inches (0.762 cm).
- the cooling holes are of a small diameter to improve cooling efficiency.
- removal of the material from the cooling holes after coating is a major problem.
- Various schemes such as chemical dissolution, grit blasting, and mechanical means are employed. Most commonly, hand removal of the powder material is performed. Since each blade may contain 100 to 300 cooling holes, the time required to probe each passageway with a thin piano wire probe to remove the sintered pack material is significant. Further, even assuming that the time was not a factor, it is often found that the material can simply not be removed by mechanical means and that the holes must be redrilled (and of course, the redrilled holes will not have a protective coating on their walls).
- the present invention comprises a pre-treatment process which largely eliminates the packing and sintering of the pack coating material in the cooling holes of the gas turbine engine hardware during the pack coating process.
- the cooling holes and other similar small intricate passages are filled in whole or in part with an organic material which is soluble in an organic solvent.
- the organic material serves to partly or completely eliminate the intrusion of the pack coating material into the fine holes during the coating process.
- the organic material decomposes to harmless vapors which exit the pack with the flow of the inert or reducing gases which are part of the normal pack coating process.
- the organic material is applied as a liquid and then solidifies to a durable state which will prevent the pack coating materials from completely filling the passageways.
- the function of the organic material is to reduce the packing density of the pack coating material in the passageways.
- the organic material performs a physical rather than a chemical function. Thus, there are a wide range of materials from which the organic material can be selected.
- a primary requirement of the organic material is that it decomposes without producing vapors which interfere with the coating process and without leaving behind a residue which would contaminate the superalloy surface or otherwise interfere with the diffusion of aluminum into that surface.
- Heavy metals such as Pb, Sn, Bi, and Hg and reactive elements such as S should be avoided, also a low carbon residual is desired.
- the organic material preferably has a viscosity at the application conditions of between 500 centistokes and 100 centistokes. Materials with this viscosity flow properly into cooling holes having the previously mentioned dimensions.
- a host of organic materials can be conceived of, which are organic soluble materials.
- Such materials include shellac, varnishes, silicones, rubbers, materials such as rubber cement, and the like. As previously indicated, these materials are functional in the context of the present invention but are not desired for reasons external to the direct function of the invention.
- the previously-mentioned materials are all materials which are soluble in a solvent and which solidify by evaporation. Materials which are liquid at the time of application and solidify by a chemical reaction such as the epoxies may also be used. It is also possible to consider the use of thermo plastic materials such as waxes. Such materials can be melted at a relatively low temperature and applied by brushing or immersion and then solidify upon cooling.
- an appropriate fugitive organic material After an appropriate fugitive organic material has been selected, and prepared in the right viscosity, it is applied to the part, preferably by brushing, although immersion and spraying are also possible alternatives.
- the organic material will be preferentially retained in the fine passages by surface tension. Any excess organic material can be removed from the surface of the part, for example, rubbing with a sprayer cloth, by air blasting with materials such as walnut shells, etc., or possibly by a short immersion in an appropriate solvent.
- the invention has been used in circumstances and with organic materials which produce essentially complete blockage of the fine cooling holes and with lower viscosity organic materials which only produce a coating on the internal surface of the holes. Both alternatives seem to work well and neither is preferred over the other. For the circumstance in which the organic material forms a coating on the internal surfaces of the hole, coating thicknesses of at least 0.0005 inches (0.0013 cm) are preferred and preferably a coating of at least 0.0010 inches (0.0025 cm) are more preferred.
- the pack coating process for the application of aluminide coatings is well known, however it will be briefly described below.
- the pack for the application of aluminide coatings contains a source of aluminum, a halide activator, and an inert ceramic material.
- a number of aluminum sources are possible for use in pack coatings which can be practiced in accordance with the present invention, for example, pure aluminum powder may be used. Alloys of aluminum may also be used, for example, aluminum - 10% silicon is used in conventional pack aluminide coatings and will function well in the present invention.
- U.S. Patent No.: 5,000,782 describes the use of an aluminum yttrium silicon alloy containing from 2% weight to 20% weight yttrium, from 6% to 50% of a material selected from the group consisting of silicon, chromium, cobalt, nickel, titanium, and mixtures thereof balance aluminum. In this latter instance, the resultant aluminide coating contains a mixture of aluminum and yttrium. The yttrium provides benefits in enhanced oxidation resistance.
- aluminum compounds may be used, for example Co 2 Al 5 , CrAl, and Fe 2 Al 5 are known as aluminum sources for pack coating processes and will work well in the present invention.
- the halide activator compound can be any one of the large number of halide compounds, including for example aluminum fluoride, sodium fluoride, sodium chloride, sodium bromide, sodium iodine, ammonium fluoride, ammonium bifluoride, ammonium chloride, potassium fluoride, potassium chloride, potassium bromide, and potassium iodine. Mixtures of these halide compounds may also be used as well as complex compounds such as Na 3 AlF 6 . These compound activators are described in U.S. Patent No.: 4,156,042.
- the inert material is typically alumina. The extent of the sintering problem varies somewhat with the activator used and is quite pronounced with the ammonium bifluoride activators.
- the present invention will be better understood through consideration of the following example.
- This example is not an embodiment of the present invention which requires the organic material to be soluble in an organic solvent, rather than water as in this example.
- An organic material known as KelzanTM was employed to coat the holes prior to aluminizing.
- KelzanTM is a product of the KelCo Company of San Diego, California, division of Merck & Company.
- the KelzanTM material is a seaweed derivative and is a water soluble high molecular-weight polymer supplied in powder form.
- the KelzanTM powder was mixed with water using a rotary mixer. Approximately 2.0% to 5.0% by mass, KelzanTM, and 95% to 98% by mass, water were employed and the resultant material was mixed until it thickened to a viscosity thicker than that of honey.
- a fine bristle paintbrush was used to apply this material to the exterior surface of the turbine blades in the region where the holes intersected with the outer surface.
- the paintbrush was manipulated so as to force the KelzanTM mixture into the cooling holes to the extent possible.
- Initial experiments used multiple KelzanTM applications with intervening drying steps in a heated oven to drive off the aqueous binder. In initial experiments the holes were completely filled with KelzanTM material.
- Subsequent experiments used fewer KelzanTM coats, and it has been found that a KelzanTM coat having a thickness after drying of as little as 0.001 inches (0.0025 cm) can be effective in reducing sintering of the pack material to the cooling hole walls during the aluminide coating process.
- the blade with the partially filled cooling passages was immersed in a pack mixture containing (by weight) 8% Al, 22% Cr, 1/2% to 1/2% ammonium bifluoride, balance 60 mesh alumina powder.
- the embedded blades were contained in a superalloy sheet metal container which was placed in a furnace with a flowing atmosphere of argon and heated to 2,025°F (1107 °C) for 26 hours. At the conclusion of this temperature cycle, the blades were removed and the pack material was removed from the surface of the blades with a gentle grit-blasting application.
- a typical blade coated according to the prior art without the preliminary organic coating was found to require approximately 2 to 10 hours of hand labor to laboriously probe and remove the pack material from the cooling holes. Often this was found to be impossible and the material had to be removed through chemical means or by redrilling the holes at substantial cost.
- the amount of labor and costs involved at removing the pack material from the cooling holes after the pack coating process is substantially reduced.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Powder Metallurgy (AREA)
Claims (13)
- Verfahren zur Beschichtung von metallischen Gegenständen, die Kühlöffnungen enthalten, mit einer Schutzbeschichtung, aufweisend das Einbetten des Gegenstands in ein Pulvergemisch, das eine Quelle der Schutzbeschichtungs-Bestandteile, einen Halogenid-Aktivator und ein inertes keramisches Material enthält, und das Erwärmen des Gegenstands und des Pulvergemisches auf eine erhöhte Temperatur,
dadurch gekennzeichnet, dass die Öffnungen vor dem Einbetten des Gegenstands in das Pulvergemisch zumindest teilweise mit einem organischen Material gefüllt werden, wobei das organische Material in einem organischen Lösungsmittel löslich ist. - Beschichtungsverfahren nach Anspruch 1, bei dem das organische Material ausgewählt wird aus der Gruppe, die besteht aus Schelllack, Firnissen, Siliconen, Kautschuken und Kautschukkitten.
- Verfahren nach Anspruch 1, bei dem sich das organische Material durch Verdampfung verfestigt.
- Beschichtungsverfahren nach Anspruch 1, bei dem sich das organische Material durch eine chemische Reaktion verfestigt.
- Verfahren nach Anspruch 4, bei dem das organische Material ein Epoxyharz ist.
- Beschichtungsverfahren nach Anspruch 1, bei dem das organische Material ein thermoplastisches Material ist.
- Verfahren nach Anspruch 6, bei dem das organische Material ein Wachs ist.
- Verfahren nach irgendeinem vorangehenden Anspruch, bei dem der Halogenid-Aktivator Ammoniumbifluorid ist.
- Verfahren nach irgendeinem vorangehenden Anspruch, bei dem die Kühlöffnungen einen Durchmesser von zwischen 0,25 und 0,64 mm (0,010 und 0,025 Inch) und eine Tiefe von zwischen 0,76 und 7,62 mm (0,030 und 0,300 Inch) haben.
- Verfahren nach irgendeinem vorangehenden Anspruch, bei dem das organische Material eine Viskosität von zwischen 5 x 10-4 und 1 x 10-4 m2/s (500 und 100 Centistoke) hat.
- Verfahren nach irgendeinem vorangehenden Anspruch, bei dem das organische Material auf den Innenoberflächen der Öffnungen eine Beschichtung von mindestens 0,013 mm (0,0005 Inch) bildet.
- Verfahren nach Anspruch 11, bei dem das organische Material auf den Innenoberflächen der Öffnungen eine Beschichtung von mindestens 0,025 mm (0,0010 Inch) bildet.
- Verfahren nach einem der Ansprüche 1 bis 11, bei dem das organische Material die Kühlöffnungen vollständig verstopft.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/187,590 US5441767A (en) | 1994-01-26 | 1994-01-26 | Pack coating process for articles containing small passageways |
US187590 | 1994-01-26 | ||
EP95909300A EP0739427B1 (de) | 1994-01-26 | 1995-01-20 | Verbessertes packzementierungsverfahren für gegenstände mit kleinen durchgängen |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95909300A Division EP0739427B1 (de) | 1994-01-26 | 1995-01-20 | Verbessertes packzementierungsverfahren für gegenstände mit kleinen durchgängen |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0861918A1 EP0861918A1 (de) | 1998-09-02 |
EP0861918B1 true EP0861918B1 (de) | 2002-04-24 |
Family
ID=22689600
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98200741A Expired - Lifetime EP0861918B1 (de) | 1994-01-26 | 1995-01-20 | Verbessertes Packzementierungsverfahren für Gegenstände mit kleinen Durchgängen |
EP95909300A Expired - Lifetime EP0739427B1 (de) | 1994-01-26 | 1995-01-20 | Verbessertes packzementierungsverfahren für gegenstände mit kleinen durchgängen |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95909300A Expired - Lifetime EP0739427B1 (de) | 1994-01-26 | 1995-01-20 | Verbessertes packzementierungsverfahren für gegenstände mit kleinen durchgängen |
Country Status (5)
Country | Link |
---|---|
US (1) | US5441767A (de) |
EP (2) | EP0861918B1 (de) |
JP (1) | JP3210345B2 (de) |
DE (2) | DE69526524T2 (de) |
WO (1) | WO1995020687A1 (de) |
Families Citing this family (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AU4424397A (en) * | 1996-09-12 | 1998-04-02 | Alon, Inc. | Chromium and silicon diffusion coating |
US5800695A (en) * | 1996-10-16 | 1998-09-01 | Chromalloy Gas Turbine Corporation | Plating turbine engine components |
US5902647A (en) | 1996-12-03 | 1999-05-11 | General Electric Company | Method for protecting passage holes in a metal-based substrate from becoming obstructed, and related compositions |
US5807428A (en) * | 1997-05-22 | 1998-09-15 | United Technologies Corporation | Slurry coating system |
US5813118A (en) * | 1997-06-23 | 1998-09-29 | General Electric Company | Method for repairing an air cooled turbine engine airfoil |
US6183811B1 (en) * | 1998-12-15 | 2001-02-06 | General Electric Company | Method of repairing turbine airfoils |
DE19859763A1 (de) * | 1998-12-23 | 2000-06-29 | Abb Alstom Power Ch Ag | Verfahren zum Unschädlichmachen von beim Beschichten mit einer Schutzschicht entstehenden Verengungen in den Kühllöchern von gasgekühlten Teilen |
US6146696A (en) * | 1999-05-26 | 2000-11-14 | General Electric Company | Process for simultaneously aluminizing nickel-base and cobalt-base superalloys |
US8278380B2 (en) | 2000-07-31 | 2012-10-02 | Los Alamos National Security, Llc | Polymer-assisted deposition of films and preparation of carbon nanotube arrays using the films |
US7604839B2 (en) * | 2000-07-31 | 2009-10-20 | Los Alamos National Security, Llc | Polymer-assisted deposition of films |
US7365118B2 (en) * | 2003-07-08 | 2008-04-29 | Los Alamos National Security, Llc | Polymer-assisted deposition of films |
US7094445B2 (en) * | 2002-05-07 | 2006-08-22 | General Electric Company | Dimensionally controlled pack aluminiding of internal surfaces of a hollow article |
US7252480B2 (en) * | 2004-12-17 | 2007-08-07 | General Electric Company | Methods for generation of dual thickness internal pack coatings and objects produced thereby |
JP5481993B2 (ja) * | 2009-07-23 | 2014-04-23 | 株式会社Ihi | アルミナイズド処理方法 |
US9206499B2 (en) | 2010-08-30 | 2015-12-08 | United Technologies Corporation | Minimizing blockage of holes in turbine engine components |
US9884343B2 (en) * | 2012-12-20 | 2018-02-06 | United Technologies Corporation | Closure of cooling holes with a filling agent |
FR3001976B1 (fr) * | 2013-02-13 | 2015-02-20 | Air Liquide | Procede de depot d'un revetement contre la corrosion |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4004047A (en) * | 1974-03-01 | 1977-01-18 | General Electric Company | Diffusion coating method |
US4156042A (en) * | 1975-04-04 | 1979-05-22 | The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland | Coating articles having fine bores or narrow cavities in a pack-cementation process |
US5217757A (en) * | 1986-11-03 | 1993-06-08 | United Technologies Corporation | Method for applying aluminide coatings to superalloys |
JPH0250981A (ja) * | 1988-08-12 | 1990-02-20 | Hitachi Ltd | 耐NaCl腐食部品,ガスタービンブレード及びガスタービンノズル |
US5209950A (en) * | 1989-06-19 | 1993-05-11 | Bp Chemicals (Hitco) Inc. | Composition for sic pack cementation coating of carbonaceous substrates |
DE4035790C1 (de) * | 1990-11-10 | 1991-05-08 | Mtu Muenchen Gmbh | |
JPH04236757A (ja) * | 1991-01-17 | 1992-08-25 | Mitsubishi Heavy Ind Ltd | タービン翼のマスキング方法 |
DE4215664C1 (de) * | 1992-05-13 | 1993-11-25 | Mtu Muenchen Gmbh | Verfahren zum Aufbringen von metallischen Zwischenschichten und seine Anwendung |
-
1994
- 1994-01-26 US US08/187,590 patent/US5441767A/en not_active Expired - Lifetime
-
1995
- 1995-01-20 WO PCT/US1995/000877 patent/WO1995020687A1/en active IP Right Grant
- 1995-01-20 EP EP98200741A patent/EP0861918B1/de not_active Expired - Lifetime
- 1995-01-20 DE DE69526524T patent/DE69526524T2/de not_active Expired - Lifetime
- 1995-01-20 DE DE69505786T patent/DE69505786T2/de not_active Expired - Lifetime
- 1995-01-20 EP EP95909300A patent/EP0739427B1/de not_active Expired - Lifetime
- 1995-01-20 JP JP52011595A patent/JP3210345B2/ja not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
DE69526524T2 (de) | 2002-12-05 |
EP0861918A1 (de) | 1998-09-02 |
JP3210345B2 (ja) | 2001-09-17 |
US5441767A (en) | 1995-08-15 |
JPH09508440A (ja) | 1997-08-26 |
WO1995020687A1 (en) | 1995-08-03 |
DE69526524D1 (de) | 2002-05-29 |
EP0739427A1 (de) | 1996-10-30 |
EP0739427B1 (de) | 1998-11-04 |
DE69505786T2 (de) | 1999-06-10 |
DE69505786D1 (de) | 1998-12-10 |
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